The recently discovered ( \{RE\} ) 12 Co 5 Bi (where \{RE\} is a rare-earth element) system has a rich magnetic phase diagram. In this paper, we report studies on polycrystalline samples of \{RE\} = Tb , Gd and Tm in order to obtain local magnetic information on the samples. In low fields, the Tb and Gd compounds show a magnetic transition at ≈ 75 and ≈ 100 K , respectively, while there is no evidence of a magnetic transition down to 3 K in the Tm sample. These results are compared with bulk magnetization measurements. The magnetic ground state in Tm 12 Co 5 Bi appears to be dramatically different in low compared to high fields, indicative of a meta-magnetic transition.